1. Field of the Invention
The present invention relates to American football, and more particularly to a more durable American football which is supported with construction liner for better supporting with lower manufacturing cost.
2. Description of Related Arts
American football is one of the most popular sports in United States. The conventional American football generally comprises a hollow outer ball carcass and an inflatable bladder disposed within the ball carcass for propping up the ball carcass after inflation. The inflatable bladder can be made of rubber or polyurethane when leather made ball carcass is used. The ball carcass of the American football comprises a plurality of cover pieces sewn edge to edge together to form an ellipsoidal shape. Each of the cover pieces comprises an outer cover skin and an inner liner for supporting between the outer cover and the inflatable rubber bladder. One of the most common materials of the outer cover skin is leather. Synthetic leather, such as polyvinyl chloride (PVC) or polyurethane (PU), is another common material for the outer cover skin because of its toughness nature that is more suitable for sewing. Besides, padded cover pieces are suggested in U.S. Pat. Nos. 4,462,590 and 4,660,831.
Generally speaking, if the ball carcass is made of leather, no backing is required. However, for polyvinyl chloride made ball carcass, woven fabric backing is attached on its inner surface for reinforcing and supporting. Also, for polyurethane made ball carcass, non-woven fabric is attached on its inner surface for reinforcing and supporting.
The liner of all the conventional American football can be of woven fabric, such as twilled nylon, cotton or other mixing material such as TC, TR, is preferably about 0.038 cm thick. To produce the conventional liner, a polyvinyl chloride or polyurethane layer and at least two lining layers are pressed to adhere on both sides of the polyvinyl chloride or polyurethane layer by feeding through a pair of pressing rollers to form a bolt of lining cloth. Pieces of inner liner with elliptical shape are cut from this lining cloth.
However, it is well known that the conventional American football is quite stiff to grip, catch and hold. It is because the inner liner, made of polyurethane and woven fabric layers adhered with each other, must be strong enough to support the softer outer cover skin to tolerate impact and to retain the ellipsoidal shape of the American football.